Structure of Right-Handed Neutrino Mass Matrix

Abstract

Recently, Nishiura and the author have proposed a unified quark-lepton mass matrix model under a family symmetry U(3)$\times$U(3)${}^{\prime }$. The model can give excellent parameter-fitting to the observed quark and neutrino data. The model has a reasonable basis as far as the quark sector, but the form of the right-handed neutrino mass matrix $M_R$ does not have a theoretical grand, that is, it was nothing but a phenomenological assumption. In this paper, it is pointed out that the form of $M_R$ is originated in structure of neutrino mass matrix for $({\nu }_i,N_{\alpha })$ where ${\nu }_i$ ($i=1,2,3$) and $N_{\alpha }$ ($\alpha =1,2,3$) are U(3)-family and U(3)${}^{\prime }$-family triplets, respectively.

Comments: 7 pages, no figure